Automatically exit diod once last export has been clunked by the last client

[Rudd-O]

Hi! I am running automated testing of diod and I would like a mechanism to make diod exit gracefully once all clients have signaled unmount (via clunk) of all attached file systems. Is this possible? If so, how? If not, how hard would it be to add this?

[Rudd-O]

I looked at the code and I can't find for the life of me on which data structures diod tracks what is mounted where.

An equivalent ask would be to ensure that some external program is called, or some log record is written, when a file system is attached or detached by a client. This would allow me to track what diod is doing and exit it cleanly when done.

[garlick]

Haven't done much with diod internals in a while, so I don't have a ready answer off the top of my head.

I think the data structure you are looking for is struct Npconn (in libnpfs).

The server can log each 9P message if you run it with -d 1 -L filename.

One way to get a diod process to run for the lifetime of one mount is to pass it a file descriptor representing one client instead of telling it to listen for connections. Use the --rfdno / --wfdno diod options. For example see tests/kern/runtest and tests/kern/kconjoin.c.

[Rudd-O]

Thanks for your kind answer! I tracked down the issue and my client process was not closing its FDs, therefore remaining open, and keeping diod alive. You are awesome.

[Rudd-O]

(This would still be a nice feature request, if you'd like to reopen it.)

[garlick]

Glad you sorted it!

May I ask what the goal of your testing is and whether your work is open source? My intention is to redo the diod CI test suite at some point (#61, #26, etc) so maybe your work will be useful at that time?

[Rudd-O]

My work is definitely open source, and here it is: https://github.com/Rudd-O/qubes-shared-folders . I am using diod as a transport between qubes, because none of the other alternatives fulfill the requirements of:

1. zero configuration
2. tiny codebase
3. easily remotable
4. easily automatable

Thanks for such an amazing project!

[garlick]

Looks quite neat! Thanks for that.